Grieving pet owners were still waiting for answers Monday as the U.S. laboratory that identified the poison that has contaminated 95 brands of dog and cat food continued its search for the source of the toxin.
Scientists at the New York State Food Laboratory on Friday identified aminopterin -- used as a rodent poison and banned in the United States -- as the likely culprit in a poisoning scare that prompted the recall of nearly 100 brands of "cuts and gravy'' style dog and cat food.
Wheat gluten used in the manufacturing process by Menu Foods of Mississauga, Ont., is suspected as the source of contamination.
Department of Agriculture and Markets spokeswoman Jessica Chittenden did not know when the lab would have results from the new tests.
Scientists so far have offered no theories on how the products became contaminated in the first place.
Some pets that ate the food suffered kidney failure, and the company has confirmed the deaths of 15 cats and one dog.
Cathy Sterling, who lost her dog to kidney failure, said she believes the number is far greater, judging from the sheer volume of calls the company's 1-800 line has received.
It took Sterling several days to get through.
On Friday, Menu Foods' president and chief executive Paul Henderson said the company had spoken with 200,000 customers over the course of the week.
On Monday, Sprott Securities analyst Aleem Israel downgraded Menu Foods Income Trust (TSX:MEW.UN) from "buy" to "reduce," saying it is "much too risky" for investors to hold the units at the moment.
